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What Is Brachydactyly?

Reviewed by Dan Brennan, MD on April 20, 2021

Brachydactyly is a congenital condition that a person is born with. It leads to someone’s fingers and toes being much shorter than average compared to the general size of their body.

There are multiple types of brachydactyly that affect the fingers and toes differently. For most people, brachydactyly will not affect how they live their lives.

Here’s everything you need to know about the causes and effects of brachydactyly on your health.

Causes of Brachydactyly

Genes. Most types of brachydactyly are genetic, which means that they can be passed down in a family. It’s a dominant genetic trait, so only one parent needs to have the condition for a child to inherit it. If you have brachydactyly, other people in your family most likely have it as well.

Many cases of brachydactyly occur without any other health conditions. You can have brachydactyly and no other health conditions. In this case, you simply have shorter fingers or toes than you might have otherwise. You may not even know that you have brachydactyly unless you get a hand or foot x-ray for another condition.

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Medications. In some cases, brachydactyly may be caused by medications a mother takes while pregnant. If an expectant mother takes anticonvulsant medication to treat epilepsy or other conditions, there is a risk of the baby developing brachydactyly. 

It can also be caused by poor blood flow in growing babies. In both of these cases, brachydactyly is not genetic. This means there may not be anyone else in the family with the condition.

Syndromes. Other conditions that people are born with called syndromes can produce shortened digits. People with Down syndrome may also have brachydactyly. 

Babies born with Cushing’s syndrome may also have brachydactyly. In these cases, the shortened finger and toe bones are part of a larger overall syndrome that affects many parts of the body.

Types of Brachydactyly

Because there are so many genes that can potentially cause brachydactyly, there are five distinct forms that you may have. Each form affects different fingers and toes.

Type A. This form of brachydactyly affects the middle bones of your fingers. It’s broken down into three sub-types. Type A1 shortens the middle bone of all of your fingers. Type A2 shortens just the middle bone of the index and sometimes the little finger. Type A3 only shortens the middle bone of the little finger.

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Type B. This type of brachydactyly affects the final bones of all eight fingers. It causes the bone to be shortened or missing entirely. The same thing happens to the corresponding toes. The final thumb bones and big toe bones may be split or flatter than average.

Type C. This rare form of brachydactyly only affects three fingers on each hand. The index, middle, and little finger will have their middle bone shortened. The ring finger won’t be affected. As a result, Type C brachydactyly will leave the ring finger as the longest on your hand.

Type D. This is the most common form of brachydactyly. It shortens the final bone in the thumbs and doesn’t affect the fingers at all.

Type E. This is the rarest form of brachydactyly. It is most often part of another condition that someone is born with. Type E shortens the bones in the hands and feet along with the bottom bone in the fingers. Instead of making your fingers and toes look shorter, it makes your hands and feet look smaller.

Impact of Brachydactyly on Your Health

Brachydactyly rarely affects your overall health. Only in rare, extreme cases will brachydactyly make it difficult to perform tasks. Otherwise, you will only experience health impacts if brachydactyly occurs in combination with another health condition.

If brachydactyly is connected to another syndrome, it can sometimes help healthcare professionals identify the main cause. In young children, brachydactyly can help doctors identify Cushing’s syndrome. In this scenario, the brachydactyly does not affect your child’s health. Rather, it is a symptom of another condition that may be impacting their well-being.

How to Prevent Brachydactyly From Affecting Your Health

For most people, unaccompanied brachydactyly won’t affect their health at all. It may occasionally cause some inconveniences. It might be more difficult to find gloves and shoes that fit appropriately. However, it should not impact their daily lives.

If you have brachydactyly that’s accompanied by another condition, then treating the other condition will generally impact your life the most. Treating Cushing’s syndrome, for example, may not resolve the brachydactyly. Yet it may improve your quality of life in many other areas.

In rare, severe cases of brachydactyly, your doctor may recommend that you use physical therapy. This is generally recommended if your brachydactyly is so significant that it affects your ability to walk or hold objects. In this case, physical therapy can help improve the range of motion, strength, and functionality in your affected fingers or toes.

WebMD Medical Reference

Sources

SOURCES:

American Journal of Medical Genetics: “Antiepileptic drugs and pregnancy outcomes.”

‌Boston Children’s Hospital: “Brachydactyly Symphalangism and Synostoses.”

‌Genetic and Rare Diseases Information Center: “Cushing’s syndrome,” “Down syndrome.”

Journal of Medical Genetics: “Clinical and radiological assessment of a family with mild brachydactyly type A1: the usefulness of metacarpophalangeal profile.”

MAYO CLINIC: “Cushing syndrome.”

Orphanet Journal of Rare Diseases: “Brachydactyly.”

‌Texas Children’s Hospital: “Symbrachydactyly.”

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